SLING-2405 : Startup synchronization problems
git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1242040 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/sling/launchpad/installer/impl/ServicesListener.java b/src/main/java/org/apache/sling/launchpad/installer/impl/ServicesListener.java
index 5e06ee0..03f7883 100644
--- a/src/main/java/org/apache/sling/launchpad/installer/impl/ServicesListener.java
+++ b/src/main/java/org/apache/sling/launchpad/installer/impl/ServicesListener.java
@@ -35,8 +35,7 @@
/**
* The <code>ServicesListener</code> listens for the required services
- * and starts/stops the scanners based on the availability of the
- * services.
+ * and starts the installation support if all services are available.
*/
public class ServicesListener {
@@ -52,44 +51,45 @@
/** The listener for the startup handler. */
private final Listener startupListener;
+ /** The registration of the launchpad listener. */
private ServiceRegistration launchpadListenerReg;
+ /** Boolean marker to not reprocess things. */
private volatile boolean installed = false;
+ /**
+ * Start listeners
+ */
public ServicesListener(final BundleContext bundleContext) {
this.bundleContext = bundleContext;
this.installerListener = new Listener(OsgiInstaller.class.getName());
this.providerListener = new Listener(LaunchpadContentProvider.class.getName());
this.startupListener = new Listener(StartupHandler.class.getName());
+ this.startupListener.start();
this.installerListener.start();
this.providerListener.start();
- this.startupListener.start();
}
+ /**
+ * Notify of service changes from the listeners.
+ * If all services are available, register listener and pass resources
+ * to the OSGi installer.
+ */
public synchronized void notifyChange() {
// check if all services are available
final OsgiInstaller installer = (OsgiInstaller)this.installerListener.getService();
final LaunchpadContentProvider lcp = (LaunchpadContentProvider)this.providerListener.getService();
-
- if ( installer != null && lcp != null ) {
- if ( !installed ) {
- installed = true;
- LaunchpadConfigInstaller.install(installer, lcp);
- }
- }
final StartupHandler handler = (StartupHandler)this.startupListener.getService();
- if ( handler != null ) {
- if ( launchpadListenerReg == null ) {
+
+ if ( installer != null && lcp != null && handler != null ) {
+ if ( !this.installed ) {
+ this.installed = true;
final LaunchpadListener launchpadListener = new LaunchpadListener(handler);
final Dictionary<String, Object> props = new Hashtable<String, Object>();
props.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Launchpad Startup Listener");
props.put(Constants.SERVICE_VENDOR, "The Apache Software Foundation");
- launchpadListenerReg = this.bundleContext.registerService(InstallationListener.class.getName(), launchpadListener, props);
- }
- } else {
- if ( launchpadListenerReg != null ) {
- launchpadListenerReg.unregister();
- launchpadListenerReg = null;
+ this.launchpadListenerReg = this.bundleContext.registerService(InstallationListener.class.getName(), launchpadListener, props);
+ LaunchpadConfigInstaller.install(installer, lcp);
}
}
}
@@ -101,21 +101,38 @@
this.installerListener.deactivate();
this.providerListener.deactivate();
this.startupListener.deactivate();
+ if ( this.launchpadListenerReg != null ) {
+ this.launchpadListenerReg.unregister();
+ this.launchpadListenerReg = null;
+ }
}
+ /**
+ * Helper class listening for service events for a defined service.
+ */
protected final class Listener implements ServiceListener {
+ /** The name of the service. */
private final String serviceName;
- private ServiceReference reference;
- private Object service;
+ /** The service reference. */
+ private volatile ServiceReference reference;
+ /** The service. */
+ private volatile Object service;
+
+ /**
+ * Constructor
+ */
public Listener(final String serviceName) {
this.serviceName = serviceName;
}
+ /**
+ * Start the listener.
+ * First register a service listener and then check for the service.
+ */
public void start() {
- this.retainService();
try {
bundleContext.addServiceListener(this, "("
+ Constants.OBJECTCLASS + "=" + serviceName + ")");
@@ -123,15 +140,26 @@
// this should really never happen
throw new RuntimeException("Unexpected exception occured.", ise);
}
+ this.retainService();
}
+ /**
+ * Unregister the listener.
+ */
public void deactivate() {
bundleContext.removeServiceListener(this);
}
+ /**
+ * Return the service (if available)
+ */
public synchronized Object getService() {
return this.service;
}
+
+ /**
+ * Try to get the service and notify the change.
+ */
private synchronized void retainService() {
if ( this.reference == null ) {
this.reference = bundleContext.getServiceReference(this.serviceName);
@@ -146,6 +174,9 @@
}
}
+ /**
+ * Try to release the service and notify the change.
+ */
private synchronized void releaseService() {
if ( this.reference != null ) {
this.service = null;
@@ -159,9 +190,9 @@
* @see org.osgi.framework.ServiceListener#serviceChanged(org.osgi.framework.ServiceEvent)
*/
public void serviceChanged(ServiceEvent event) {
- if (event.getType() == ServiceEvent.REGISTERED && this.service == null ) {
+ if (event.getType() == ServiceEvent.REGISTERED) {
this.retainService();
- } else if ( event.getType() == ServiceEvent.UNREGISTERING && this.service != null ) {
+ } else if ( event.getType() == ServiceEvent.UNREGISTERING ) {
this.releaseService();
}
}
